Developing an efficient garnet-type near-infrared phosphor Na1.5Gd1.5Sc2Ge3O12:Cr3+ with relatively long-wavelength emission

Developing efficient near-infrared (NIR) phosphor with an emission peak wavelength over 850 nm is crucial to realize multi-functional spectroscopy applications, while this remains a significant challenge. Herein, a garnet-type Na_1.5Gd_1.5Sc₂Ge₃O₁₂:Cr³⁺ phosphor with an emission peak located at 882 nm was created from NaδGdδCa_3-2δSc₂Ge₃O₁₂:Cr³⁺ (0 ≤ δ ≤ 1.5) solid solutions basing on the effect of cationic disorder. The maximum internal quantum efficiency (IQE) of Na_1.5Gd_1.5Sc_2-xGe₃O₁₂:xCr³⁺ reached 84.6% when x = 0.01. The maximum external quantum efficiency (EQE) can be optimized to 20.6%. Using this material, a prototype NIR phosphor-converted light-emitting diodes (pc-LEDs) device was fabricated, which demonstrates an excellent prospect in spectroscopy applications.